This invention relates generally to automatic circuit board assembly and is particularly directed to the delivery of electronic components for automatic mounting on a circuit board.
The high speed assembly of circuit boards makes use of automatic component insertion equipment for the positioning of electronic components upon the circuit board, or substrate. The component is positioned upon a first side of a circuit board with its conductive leads inserted through predrilled apertures in the board. The component leads are then crimped on a second side of the circuit board for electrical coupling with linear conductors typically in the form of metal foil. In this type of automatic circuit board assembly arrangement, a conveyor typically displaces the board to sequentially arranged work stations whereat various components are mounted to the circuit board by means of a numerically controlled component insertion apparatus. Because the economics of circuit board assembly requires high speed operation and the aforementioned component insertion apparatus typically possesses limited positioning and component grasping flexibility, a highly accurate component delivery arrangement is required for proper positioning and orientation of the electronic component prior to engagement by the automatic insertion apparatus.
One prior art arrangement for the delivery of electronic components to automatic insertion apparatus is disclosed in the aforementioned application and is shown in FIG. 1. The component delivery system includes a delivery chute, or tube, 10 mounted to an elongated base 18 on which are mounted an upper air cylinder 14 and a lower air cylinder 32. The upper and lower air cylinders 14, 32 are coupled to a source of pneumatic pressure (not shown) to effect the linear displacement of cylindrical armatures 16, 26, respectively. The distal end of cylindrical armature 16 is positioned adjacent an aperture in the lower portion of delivery tube 10 through which electronic components 12 positioned therein fall under gravity for subsequent linear displacement by means of cylindrical armature 16. Extension of cylindrical armature 16 by means of the upper air cylinder 14 causes the leftward displacement of an electronic component 12A which is engaged by means of a pivoting component receiver 22. The component receiver 22 is adapted to receive and engage the leads of the electronic component 12A. The component receiver 22 is pivotally mounted to the base 18 by means of a pivot pin 30 and is further coupled to the distal end of cylindrical armature 26 by means of a drive pin 28. Retraction of cylindrical armature 26 results in the counterclockwise rotation of the component receiver 22 following the insertion of electronic component 12A therein. Rotational displacement of the component receiver 22 is limited by a lower receiver stop 24 positioned on an end portion of base 18. With the component receiver 22 rotationally displaced so as to engage the lower receiver stop 24 by means of the linear displacement of cylindrical armature 26, a gripper assembly 17 located above the component receiver 22 then engages, displaces and inserts the component 12A on a circuit board (not shown). Following removal of the electronic component 12A from the component receiver 22, cylindrical armature 16 is then retracted by the upper air cylinder 14 and the component receiver 22 is then rotated in a clockwise direction by means of cylindrical armature 26 so as to engage an upper receiver stop 20 in the base 18 in preparation for receipt of another electonic component from the delivery tube 10.
The component delivery system described above as well as other prior art approaches suffer from various limitations. For example, misalignment of the electronic components within the delivery tube frequently results in the obstruction of the delivery tube and an interruption in component delivery. In addition, the downward displacement by gravity of the electronic components through the opening in the lower portion of the delivery tube frequently causes a reorientation of the electronic component resulting in its misalignment with the component receiver or jamming of the component delivery system such that linear displacement of the component delivery armature is inhibited. Finally, delivery system component dimensional tolerances arising from the continuous, rapid movement of the component displacement means may result in the deposit of more than one component from the delivey tube into the delivery system housing causing the jamming of the component displacement means and an interruption in the component circuit board mounting procedure.
These and other limitations of the prior art are eliminated in the improved component delivery system of the present invention which provides for the controlled release of electronic components from a delivery tube and the stabilizing of the component upon exit from the delivery tube and deposit within the delivery system housing. The component is maintained in proper position and orientation during its linear displacement within the delivery system housing by means of a pivoting component retainer member and the combination of a telescoping linearly displaceable plunger pin or shaft for engaging the component and a movable, contoured carriage for receiving and supporting the component in ensuring its proper insertion within a component receiver for delivery to a robotic gripper assembly for insertion on the circuit board.